Make sure PollerBehavior is marked as Experimental (#2569)

Author: Quinn-With-Two-Ns

temporal-sdk/src/main/java/io/temporal/worker/Worker.java

@@ -616,12 +616,22 @@ private static SingleWorkerOptions toWorkflowWorkerOptions(
       maxConcurrentWorkflowTaskPollers = 2;
     }
 
+    PollerBehavior pollerBehavior = options.getWorkflowTaskPollersBehavior();
+    if (pollerBehavior instanceof PollerBehaviorSimpleMaximum) {
+      if (((PollerBehaviorSimpleMaximum) pollerBehavior).getMaxConcurrentTaskPollers() == 1) {
+        log.warn(
+            "WorkerOptions.Builder#setWorkflowTaskPollersBehavior was set to {}. This is an illegal value. The number of Workflow Task Pollers is forced to 2. See documentation on WorkerOptions.Builder#setWorkflowTaskPollersBehavior",
+            pollerBehavior);
+        pollerBehavior = new PollerBehaviorSimpleMaximum(2);
+      }
+    }
+
     return toSingleWorkerOptions(factoryOptions, options, clientOptions, contextPropagators)
         .setPollerOptions(
             PollerOptions.newBuilder()
                 .setPollerBehavior(
-                    options.getWorkflowTaskPollersBehavior() != null
-                        ? options.getWorkflowTaskPollersBehavior()
+                    pollerBehavior != null
+                        ? pollerBehavior
                         : new PollerBehaviorSimpleMaximum(maxConcurrentWorkflowTaskPollers))
                 .setUsingVirtualThreads(options.isUsingVirtualThreadsOnWorkflowWorker())
                 .build())

temporal-sdk/src/main/java/io/temporal/worker/WorkerOptions.java

@@ -496,6 +496,10 @@ public Builder setDeploymentOptions(WorkerDeploymentOptions deploymentOptions) {
     /**
      * Set the poller behavior for workflow task pollers.
      *
+     * <p>Note: If the poller behavior is set to {@link PollerBehaviorSimpleMaximum}, the maximum
+     * number of concurrent workflow task pollers must be at least 2 to account for the sticky and
+     * non-sticky task poller. If it is set to 1 it will be automatically adjusted to 2.
+     *
      * <p>If the sticky queue is enabled, the poller behavior will be used for the sticky queue as
      * well.
      */
@@ -866,34 +870,42 @@ public String getIdentity() {
     return identity;
   }
 
+  @Experimental
   public boolean isUsingVirtualThreadsOnWorkflowWorker() {
     return usingVirtualThreadsOnActivityWorker;
   }
 
+  @Experimental
   public boolean isUsingVirtualThreadsOnActivityWorker() {
     return usingVirtualThreadsOnActivityWorker;
   }
 
+  @Experimental
   public boolean isUsingVirtualThreadsOnLocalActivityWorker() {
     return usingVirtualThreadsOnLocalActivityWorker;
   }
 
+  @Experimental
   public boolean isUsingVirtualThreadsOnNexusWorker() {
     return usingVirtualThreadsOnNexusWorker;
   }
 
+  @Experimental
   public WorkerDeploymentOptions getDeploymentOptions() {
     return deploymentOptions;
   }
 
+  @Experimental
   public PollerBehavior getWorkflowTaskPollersBehavior() {
     return workflowTaskPollersBehavior;
   }
 
+  @Experimental
   public PollerBehavior getActivityTaskPollersBehavior() {
     return activityTaskPollersBehavior;
   }
 
+  @Experimental
   public PollerBehavior getNexusTaskPollersBehavior() {
     return nexusTaskPollersBehavior;
   }

temporal-sdk/src/main/java/io/temporal/worker/tuning/PollerBehavior.java

@@ -1,5 +1,7 @@
 package io.temporal.worker.tuning;
 
+import io.temporal.common.Experimental;
+
 /**
  * Defines the behavior of a poller.
  *
@@ -8,4 +10,5 @@
  * PollerBehaviorSimpleMaximum}. For all intents and purpose this interface should be considered
  * sealed.
  */
+@Experimental
 public interface PollerBehavior {}

temporal-sdk/src/main/java/io/temporal/worker/tuning/PollerBehaviorAutoscaling.java

@@ -1,5 +1,6 @@
 package io.temporal.worker.tuning;
 
+import io.temporal.common.Experimental;
 import java.util.Objects;
 
 /**
@@ -9,6 +10,7 @@
  * <p>If the server does not support autoscaling, then the number of pollers will stay at the
  * initial number of pollers.
  */
+@Experimental
 public final class PollerBehaviorAutoscaling implements PollerBehavior {
   private final int minConcurrentTaskPollers;
   private final int maxConcurrentTaskPollers;

temporal-sdk/src/main/java/io/temporal/worker/tuning/PollerBehaviorSimpleMaximum.java

@@ -1,11 +1,13 @@
 package io.temporal.worker.tuning;
 
+import io.temporal.common.Experimental;
 import java.util.Objects;
 
 /**
  * A poller behavior that will attempt to poll as long as a slot is available, up to the provided
  * maximum. Cannot be less than two for workflow tasks, or one for other tasks.
  */
+@Experimental
 public class PollerBehaviorSimpleMaximum implements PollerBehavior {
   private final int maxConcurrentTaskPollers;